Let's be fair here. Those relationships are between existing characters from canon. Characters who are MUCH less likely to be killed off in stories than any other character.

Not for nothing, but Trip was dead in canon until TrekLit revived him in part to pair him with T'Pol.

If a qualifier is required, I am a straight person. With that said, I take away something completely different from Ranul Keru. I think that his monkish life is very meaningful. It shows the depths of a love that was lost and has not been, and may never be, replaced. He experienced something rare for a person of any persuasion and he treasures that. I think that his situation is profound and I kind of hope that he stays monkish (and has a really big adventure). I'd prefer that the relationship you want to see be depicted with other characters.

I don't necessarily think it needs to be Ranul either, but he an T'Prynn are probably the highest profile of TrekLit's LGBT characters (I'm sorry, I wasn't a fan of either SCE or NF), and I guess I tend to notice them the most.